Certain 3-(substituted benzoyl)-3:2:1-bicyclooctan-2,4-diones

ABSTRACT

Herbicidal compounds of the formula ##STR1## wherein R is halogen; C 1  -C 2  alkyl; C 1  -C 2  alkoxy; trifluoromethoxy; difluoromethoxy; nitro; cyano; C 1  -C 2  haloalkyl; R a  SO n  - wherein n is 0 or 2 and R a  is C 1  -C 2  alkyl, trifluoromethyl or difluoromethyl; 
     R 1  is hydrogen or C 1  -C 4  alkyl; 
     R 2  is hydrogen or C 1  -C 4  alkyl; 
     R 3  is hydrogen or C 1  -C 4  alkyl; 
     R 4  is hydrogen or C 1  -C 4  alkyl; and 
     R 5  and R 6  independently are (1) hydrogen; (2) halogen; (3) C 1  -C 4  alkyl; (4) C 1  -C 4  alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C 1  -C 4  haloalkyl; (9) R b  SO n  - wherein n is the integer 0, 1 or 2; and R b  is (a) C 1  -C 4  alkyl; (b) C 1  -C 4  alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR c  R d  wherein R c  and R d  independently are hydrogen or C 1  -C 4  alkyl; (11) R e  C(O)- wherein R e  is C 1  -C 4  alkyl or C 1  -C 4  alkoxy; or (12) --SO 2  NR c  R d  wherein R c  and R d  are as defined; and (13) --N(R c )C(O)R d  wherein R c  and R d  are as defined; and their salts.

BACKGROUND OF THE INVENTION

European Patent Application Nos. 135,191; 186,118, 186,119 and 186,120 relate to certain herbicidal compounds that can have the following structural formula ##STR2## wherein R through R⁶ are substantially as defined below and R⁷ and R⁸ are hydrogen or alkyl.

DESCRIPTION OF THE INVENTION

This invention relates to 3-(substituted benzoyl)-3:2:1-bicyclooctan-2,4-diones and their use as herbicides.

One embodiment of this invention is an herbicidal composition comprising an herbicidally active 3-(substituted benzoyl)-3:2:1-bicyclooctane and an inert carrier therefor. The 1-, 5- and 8-positions of the 3:2:1-bicyclooctan-2,4-dione are preferably substituted with groups hereinafter defined, most preferably hydrogen or methyl groups. The benzoyl moiety can be substituted, preferably with the groups hereinafter recited.

Also embodied within the scope of this invention are novel compounds having the following structural formula ##STR3## wherein

R is halogen; C₁ -C₂ alkyl, preferably methyl; C₁ -C₂ alkoxy, preferably methoxy, trifluoromethoxy or difluoromethoxy; nitro; cyano; C₁ -C₂ haloalkyl, preferably trifluoromethyl; R^(a) SO_(n) -- wherein n is the integer 0, 1 or 2, preferably 2, and R^(a) is C₁ -C₂ alkyl, preferably methyl, trifluoromethyl or difluoromethyl; more preferably R is chlorine, bromine, methyl, methoxy, trifluoromethyl, cyano, nitro, C₁ -C₂ alkylthio or C₁ -C₂ alkylsulfonyl; most preferably R is chlorine, nitro, methyl, trifluoromethyl or methylsulfonyl;

R¹ is hydrogen or C₁ -C₄ alkyl, preferably methyl;

R² is hydrogen or C₁ -C₄ alkyl, preferably methyl;

R³ is hydrogen or C₁ -C₂ alkyl, preferably methyl;

R⁴ is hydrogen or C₁ -C₄ alkyl, preferably methyl; and

R⁵ and R⁶ are independently (1) hydrogen; (2) halogen, preferably chlorine, fluorine or bromine; (3) C₁ -C₄ alkyl, preferably methyl; (4) C₁ -C₄ alkoxy, preferably methoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl, preferably trifluoromethyl; (9) R^(b) SO_(n) -- where in n is the integer 0, 1 or 2, preferably 2; and

R^(b) is (a) C₁ -C₄ alkyl, preferably methyl;

(b) C₁ -C₄ alkyl substituted with halogen or cyano, preferably chloromethyl, trifluoromethyl or cyanomethyl;

(c) phenyl; or

(d) benzyl;

(10) NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl;

(11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy;

(12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; or

(13) --N(R^(c))C(O)R^(d) wherein R^(e) and R^(d) are as defined.

Preferably, R⁵ is in the 3-position. More preferably R⁵ is hydrogen, chlorine, fluorine, trifluoromethyl, cyano, C₁ -C₄ alkoxy or C₁ -C₄ alkylthio. Most preferably R⁵ is hydrogen. Preferably R⁶ is in the 4-position. Most preferably R⁶ is hydrogen, cyano, trifluoromethyl, or R^(b) SO₂ wherein R^(b) is C₁ -C₄ alkyl, preferably methyl or C₁ -C₄ haloalkyl, preferably chloromethyl, difluoromethyl or triluoromethyl.

The term "C₁ -C₄ alkyl" includes methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and t-butyl. The term "halogen" includes chlorine, bromine, iodine and fluorine. The terms "C₁ -C₄ alkoxy" includes methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy and t-butoxy. The term "C₁ -C₄ haloalkyl" includes the alkyl groups defined above under C₁ -C₄ alkyl in which one or more hydrogens is replaced by chlorine, bromine, iodine or fluorine.

When R¹ and R² are not identical, then two optical isomers of the compound are possible, i.e., both "R" and "S" isomers are possible. These two isomers are asymmetric mirror-images of each other and are called chiral compounds.

Salts of the above-described compounds (as defined hereinafter) are included within the scope of this invention.

The compounds of this invention can have the following four structural formulae because of tautomerism: ##STR4## wherein R, R¹, R², R³, R⁴, and R⁵ and R⁶ are as defined above.

The circled proton on each of the four tautomers is reasonably labile. These protons are acidic and can be removed by reaction with a base to form a salt having an anion of the following four resonance forms: ##STR5## wherein R, R¹, R², R³, R⁴, R⁵ and R⁶ are as defined above.

Examples of cations of these bases are inorganic cations such as alkali metals, e.g. lithium, sodium and potassium; the alkaline earth metals, e.g. calcium and magnesium or ammonium or organic cations such as substituted ammonium, sulfonium, sulfoxonium or phosphonium wherein the substituents are aliphatic or aromatic groups.

Those skilled in the art will recognize in considering the salts of this invention that varying degrees of association between the anion and cation will exist depending upon the nature of the cation. In some instances with a suitable cation, such as copper, the salt can exist in a chelated form.

The compounds of this invention and their salts are active herbicides of a general type. That is, they are herbicidally effective against a wide range of plant species. The method of controlling undesirable vegetation of the present invention comprises applying an herbicidally effective amount of the above-described compounds or their salts to the area where control is desired.

The compounds of the present invention can be prepared by either of two general methods.

The first process proceeds via the production of an enol ester intermediate as shown in reaction (1). The final product is obtained by rearrangement of the enol ester as shown in reaction (2).

The process is conducted in the presence of a catalytic amount of a source of cyanide anion and/or hydrogen cyanide, together with a molar excess, with respect to the enol ester, of a moderate base.

The two reactions may be conducted as separate steps by isolation and recovery of the enol ester using conventional techniques prior to conducting step (2), or by addition of a cyanide source to the reaction medium after the formation of the enol ester, or in one step by inclusion of the cyanide source at the start of reaction (1). ##STR6## wherein R through R⁶ and moderate base are as defined and Y is halogen, preferably chlorine, C₁ -C₄ alkyl-C(O)--O--, C₁ -C₄ alkoxy-C(O)--O-- or ##STR7## wherein, R, R⁵ and R⁶ in this portion of the molecule are identical with those in the reactant shown above and the moderate base is as defined, preferably tri-C₁ -C₆ alkylamine, alkali metal carbonate or alkali metal phosphate.

Generally, in step (1) mole amounts of the dione and substituted benzoyl reactant are used, along with a mole amount or excess of the base. The two reactants are combined in an organic solvent such as methylene chloride, toluene, ethyl acetate or dimethylformamide. The base or benzoyl reactant preferably is added to the reaction mixture with cooling. The mixture is stirred at 0°-50° C. until the reaction is substantially complete. ##STR8## wherein the moderate base and R through R⁶ are as defined above.

Generally, in step (2) a mole of the enol ester intermediate is reacted with 1 to 4 moles of the moderate base, preferably about 2 moles of moderate base and from 0.01 mole to about 0.5 mole or higher, preferably about 0.01-0.1 mole of the cyanide source. The mixture is stirred in a reaction pot until the rearrangement is substantially complete at a temperature below 50° C., preferably about 20° C. to about 40° C., and the desired product is recovered by conventional techniques.

The term "cyanide source" refers to a substance or substances which under the rearrangement conditions consists of or generates hydrogen cyanide and/or cyanide anion.

Preferred cyanide sources are alkali metal cyanides such as sodium and potassium cyanide; cyanohydrins of methyl alkyl ketones having from 1-4 carbon atoms in the alkyl groups, such as acetone or methyl isobutyl ketone cyanohydrins; benzaldehyde cyanohydrin; cyanohydrins of C₂ -C₅ aliphatic aldehydes such as acetaldehyde cyanohydrin, cyanohydrin, etc.; cyclohexanone cyanohydrin; lactonitrile; zinc cyanide, di- and tri-(lower alkyl) silyl cyanides, notably dimethyl- and trimethyl-silyl cyanide; potassium ferric cyanide; and hydrogen cyanide itself. Hydrogen cyanide is considered most advantageous as it produces relatively rapid reaction and is inexpensive. Among cyanohydrins the preferred cyanide source is acetone cyanohydrin.

The cyanide source is used in an amount up to about 50 mole percent based on the enol ester. It may be used in as little as about 1 mole percent to produce an acceptable rate of reaction at about 40° C. on a small scale. Larger scale reactions give more reproducible results with slightly higher catalyst levels of about 2 mole percent. Generally about 1-10 mole percent of the cyanide source is preferred.

The process is conducted with a molar excess, with respect to the enol ester, of a moderate base. By the term "moderate base" is meant a substance which acts as a base yet whose strength or activity as a base lies between that of strong bases such as hydroxides (which could cause hydrolysis of the enol ester) and that of weak bases such as N,N-dimethylaniline (which would not function effectively). Moderate bases suitable for use in this embodiment include both organic bases, e.g., trialkylamines such as triethylamine and inorganic bases such as alkali metal carbonates and phosphates. Suitable inorganic bases include potassium carbonate and trisodium phosphate.

The base is used in an amount of from about 1 to about 4 moles per mole of enol ester, preferably about 2 moles per mole.

When the cyanide source is an alkali metal cyanide, particularly potassium cyanide, a phase transfer catalyst may be included in the reaction. Particularly suitable phase transfer catalysts are the crown ethers.

A number of different solvents are useful in this process, depending on the nature of the acid halide or the acylated product. A preferred solvent for this reaction is 1,2-dichloroethane. Other solvents which may be employed, depending on the reactants or products include toluene, acetonitrile, methylene chloride, ethyl acetate, dimethylformamide, and methyl isobutyl ketone (MIBK).

In general, depending on the nature of the reactants and the cyanide source, the rearrangement may be conducted at temperatures up to about 50° C.

Alternatively, the compounds of the present invention may be prepared via the following general method. The process proceeds via the condensation of an anhydride and an enol ester in the presence of a Lewis acid as shown in reaction 3. ##STR9## wherein R through R⁶ are as previously defined and R⁷ is C₁ -C₅ alkyl or phenyl.

Generally, in step (3), mole amounts of the anhydride and the enol ester are used along with 2 molar equivalents of the Lewis acid. The reactants are combined in a non-protic organic solvent such as ethylene dichloride and the mixture stirred and heated at 20°-100° C. until the reaction is substantially complete. The desired product is isolated using standard techniques.

The bicylic diones can be prepared via the method of Eistert, B., Greiber D., and Casperi, J., Liebigs Am. Chem., 659, 64 (1962) or from camphorquinone via the method of Rupe, H. and Hathiger, F., Helv. Chim. Acta, 23, 139 (1939).

The anhydrides of reaction 3 can be prepared by dehydration of the corresponding diacid according to the method described in Organic Synthesis II, p. 560. The diacid itself is prepared from the corresponding bicyclic olefin via the method of R. H. Perry, J. Org. Chem. 1959, 24, 829. The enol esters of reaction 3 may be prepared via the method of W. M. Quattlebaum Jr. and C. A. Noffsinger, U.S. Pat. No. 2,466,737 (1949).

The following examples teach the synthesis of representative compounds of this invention.

EXAMPLE 1 S-1,8,8-Trimethyl-3-(2-nitro-4-trifluoromethylbenzoyl)-3:2:1-bicyclooctan-2,4-dione ##STR10##

S-1,8,8-Trimethyl-3:2:1-bicyclooctan-2,4-dione (1.8 grams [g], 10 millimoles [mmol]) and 2-nitro-4-trifluoromethylbenzoyl chloride were dissolved and stirred in 20 milliliters (mL) acetonitrile. Triethylamine (1.1 g, 10 mmol) was added dropwise and the resulting mixture stirred for 1 hour. An additional 1.1 g triethylamine was added, followed by powdered KCN (1.8 g) and 18-Crown-6 (0.18 g). The resulting mixture was stirred for 18 hours. The mixture was then poured into 150 mL ether and washed with 3 mL NaHCO₃. Extracted with 2×50 mL K₂ CO₃, the combined aqueous extracts were acidified with concentrated HCl and extracted with 2×75 mL ethyl acetate. The combined organic extracts were dried with MgSO₄ and evaporated to yield 1.3 g (33% yield) of a yellow oil.

EXAMPLE 2 3-(2-Chlorobenzoyl)-3:2:1-bicyclooctan-2,4-dione ##STR11##

2-Chloro-α-acetoxystyrene (1.96 g, 10 mmol) and cyclopentane-1,3-dicarboxylic anhydride (1.4 g, 10 mmol) were stirred in 10 mL ethylene dichloride. Aluminum chloride (2.7 g, 20 mmol) was added all at once. The resulting mixture was heated under reflux for 15 minutes, and then after cooling, poured into 1 normal (N) sodium hydroxide solution. The aqueous solution was washed with ether and then acidified with concentrated HCl. The acidic solution was extracted twice with ethyl acetate, the combined organic extracts were dried with MgSO₄ and then evaporated to give an orange oil. The orange oil was treated with ether to give a solid precipitate which was removed by filtration. Evaporation of the ether yielded the product as a yellow oil which crystallized on standing (0.54 g, 19.5%).

The following is a table of certain selected compounds that are preparable according to the procedure described hereto. Compound numbers are assigned to each compound and are used throughout the remainder of the application.

                  TABLE I                                                          ______________________________________                                          ##STR12##                                                                     Cmpd.                                                                          No.   R       R.sup.1 R.sup.2                                                                              R.sup.3                                                                              R.sup.4                                                                              R.sup.5                                                                             R.sup.6                           ______________________________________                                         1     NO.sub.2                                                                               *       *     CH.sub.3                                                                             CH.sub.3                                                                             H    H                                 2.sup.a                                                                              NO.sub.2                                                                               CH.sub.3                                                                               H     CH.sub.3                                                                             CH.sub.3                                                                             H    4-CF.sub.3                        3     NO.sub.2                                                                               H       CH.sub.3                                                                             CH.sub.3                                                                             CH.sub.3                                                                             H    4-CF.sub.3                        4.sup.b                                                                              Cl      H       H     H     H     H    H                                 5     Cl      H       H     H     H     H    4-Cl                              ______________________________________                                          .sup.a Prepared in Example 1.                                                  .sup.b Prepared in Example 2.                                                  *50:50 mixture of chiral isomers (R.sup.1 = CH.sub.3, R.sup.2 = H, and         R.sup.1  = H, R.sup.2 = CH.sub.3).                                       

The following Table shows the instrumental analysis spectral data for the compounds of Table I.

                                      TABLE I-A                                    __________________________________________________________________________     Compound                                                                       Number Spectral Data                                                           __________________________________________________________________________     1      IR (KBr film): 3120, 3080, 2980, 2880, 1680, 1580, 1480, 1450,                 1420, 1380, 1350, 1250, 1200, 1160, 1120, 1070, 860, 790, 760,                 705                                                                            MS: (m/Z): 41, 55, 69, 77, 83, 95, 109, 123, 137, 138, 150,                    199, 213, 240, 255, 283 (M.sup.+ -- NO.sub.2)                           2      H--NMR (CDCl.sub.3): 0.95 (s, CH3)*, 0.98 (s, CH.sub.3).sup.$,                 1.00 (s, CH.sub.3)*,                                                           1.01 (s, CH.sub.3)*, 1.02 (s, CH.sub.3).sup.$, 1.29 (s,                        CH.sub.3).sup.$, 1.50-2.40 (m,                                                 2CH.sub.2), 2.38 (d, CH).sup.$, 2.72 (d, CH)*, 7.42 (dd, 1H, ar.),             7.94                                                                           (d, 1H, ar.), 8.47 (d, 1H, ar.), 16.22 (bs, enol OH)*, 17.15 (bs,              enol OH).sup.$                                                                 MS (m/z): 41, 55, 69, 79, 83, 95, 110, 109, 126, 137, 144,                     172, 189, 218, 267, 351 (M.sup.+ -- NO.sub.2)                           3      MS (m/z): 41, 55, 69, 83, 95, 109, 126, 137, 144, 161, 172,                    189, 218, 267, 281, 308, 314, 323, 351 (M.sup.+ -- NO)                  4      H--NMR (CDCl.sub.3): 1.70-2.35 (m, 3CH2), 2.80-3.15 (m, 2CH),                  7.35 (m, 2H, ar.), 7.47 (m, 1H, ar.), 7.98 (d, ar.), 17.1 (b,                  enol OH)                                                                       MS (m/z: 41, 45, 55, 67, 73, 86, 97, 111, 112, 113, 139, 141,                  213, 241 (M+--Cl)                                                              IR (KBR film): 2960, 2860, 1690, 1560, 1470, 1420, 1340, 1290,                 1270, 1240, 1215, 1170, 1140, 1090, 1050, 740, 705, 550, 370            5      H--NMR (CDCl.sub.3): 1.60-2.35 (m, 3CH2), 2.85-3.15 (m, 2CH), -                7.35 (dd, 1H, ar.), 7.52 (d, 1H, ar.), 7.97 (d, 1H, ar.)                       IR (KBr pellet): 3080, 3030, 2960, 1675, 1570, 1425, 1400,                     1375, 1340, 1305, 1170, 1145, 1110, 1055, 995, 940, 870, 835,                  620                                                                            MS (m/z): EI: 79, 109, 110, 111, 112, 113, 145, 147, 149,                      155, 173, 175, 177, 233, 235, 246, 274 (M--HCl), 276.                          CI: 275, 277, 311 (MH.sup.+), 313, 315                                  __________________________________________________________________________       *Major rotational isomer                                                       .sup.$ Minor rotational isomer                                          

Herbicidal Screening Tests

As previously mentioned, the herein described compounds produced in the above-described manner are phytotoxic compounds which are useful and valuable in controlling various plant species. Selected compounds of this invention were tested as herbicides in the following manner.

Pre-emergence herbicide test. On the day preceding treatment, seeds of seven different weed species are planted in loamy sand soil in individual rows using one species per row across the width of a flat. The seeds used are green foxtail (FT) (Setaria viridis), watergrass (WG) (Echinochloa crusgalli), wild oat (WO) (Avena fatua), annual morningglory (AMG) (Ipomoea lacunosa), velvetleaf (VL) (Abutilon theophrasti), Indian mustard (MD) (Brassica jucea), and yellow nutsedge (YNG) (Cyperus esculentus). Ample seeds are planted to give about 20 to 40 seedlings per row, after emergence, depending upon the size of the plants.

Using an analytical balance, 600 milligrams (mg) of the compound to be tested are weighed out on a piece of glassine weighing paper. The paper and compound are placed in a 60 milliliter (ml) wide-mouth clear bottle and dissolved in 45 ml of acetone or substituted solvent. Eighteen ml of this solution are transferred to a 60 ml wide-mouth clear bottle and diluted with 22 ml of a water and acetone mixture (19:1) containing enough polyoxyethylene sorbitan monolaurate emulsifier to give a final solution of 0.5%) (v/v). The solution is then sprayed on a seeded flat on a linear spray table calibrated to deliver 80 gallons per acre (748 L/ha). The application rate is 4 lb/acre (4.48 kg/ha).

After treatment, the flats are placed in the greenhouse at a temperature of 70° to 80° F. and watered by sprinkling. Two weeks after treatment, the degree of injury or control is determined by comparison with untreated check plants of the same age. The injury rating from 0 to 100% is recorded for each species as percent control with 0% representing no injury and 100% representing complete control.

The results of the tests are shown in the following Table II.

                  TABLE II                                                         ______________________________________                                         Pre-Emergence Herbicidal Activity                                              Application Rate - 4.48 kg/ha                                                  Cmpd.                                                                          No.   FT      WG     WO    AMG   VL    MD   YNG                                ______________________________________                                         1     85      90     10    10    20    20   0                                  2     100     100    30    90    100   100  70                                 3     100     100    80    100   100   100  80                                 5     100     100    100   100   100   100  80                                 ______________________________________                                    

Post-Emergence Herbicide Test: This test is conducted in an identical manner to the testing procedure for the pre-emergence herbicide test, except the seeds of the seven different weed species are planted 10-12 days before treatment. Also, watering of the treated flats is confined to the soil surface and not to the foliage of the sprouted plants.

The results of the post-emergence herbicide test are reported in Table III.

                  TABLE III                                                        ______________________________________                                         Post-Emergence Herbicidal Activity                                             Application Rate - 4.48 kg/ha                                                  Cmpd.                                                                          No.   FT      WG     WO    AMG   VL    MD   YNG                                ______________________________________                                         1     0       0      0     0     0     0    0                                  2     100     100    80    100   100   100  70                                 3     100     100    90    100   100   100  70                                 5     80      60     60    80    80    100  30                                 ______________________________________                                    

Pre-Emergence Multi-Weed Herbicide Test

Several compounds were evaluated at an application rate of 1/2 lb/acre (0.56 kg/ha) for pre-emergence activity against a larger number of weed species.

Pre-Emergence Multi-Weed Herbicide Test

Several compounds were evaluated at an application rate of 1/2 lb/acre (0.56 kg/ha) for pre-emergence activity against a larger number of weed species.

The process was generally similar to the pre-emergence herbicide test described above except that only 150 or 75 milligrams of test compound were weighed out and the application rate was 40 gallons per acre.

Indian mustard (MD) was eliminated in this test and the following weed species were added:

    ______________________________________                                         Grasses:                                                                              annual ryegrass                                                                              Lolium multiflorum                                                                             (ARG)                                            shattercane   Sorghum bicolor (SHC)                                            broadleaf signalgrass                                                                        Brachiaria platyphylla                                                                         (BSG)                                            sicklepod     Cassia obtusifolia                                                                             (SP)                                             cocklebur     Xanthium sp.    (CB)                                      ______________________________________                                    

The results of the test are shown in Table IV.

                                      TABLE IV                                     __________________________________________________________________________     Pre-Emergence Multi-weed Herbicide Test                                        Application Rate - 0.56 kg/ha                                                  Cmpd.                                                                          No. FT ARG WG SHC                                                                               WO BSG                                                                               AMG VL SP                                                                               YNS                                                                               CB                                          __________________________________________________________________________     4   100                                                                               0   60 100                                                                               20 80 0   20 --                                                                               0  0                                           __________________________________________________________________________      -- = not tested                                                          

Post-Emergence Multi-Weed Herbicide Test: This test is conducted in an identical manner to the testing procedure for the post-emergence herbicide test, except the seeds of the seven weed species used in the pre-emergence multi-weed herbicide test were used and the seeds were planted 10-12 days before treatment. Also, watering of the treated flats is confined to the soil surface and not to the foliage of the sprouted plants.

The results of the post-emergence multi-weed herbicide test are reported in Table V.

                                      TABLE V                                      __________________________________________________________________________     Post-Emergence Multi-Weed Herbicidal Activity                                  Application Rate - 0.56 kg/ha                                                  Cmpd.                                                                          No. FT ARG WG SHC                                                                               WO BSG                                                                               AMG VL SP                                                                               YNS                                                                               CB                                          __________________________________________________________________________     4   10 20  20 20 20 0  0   0  0 0  0                                           __________________________________________________________________________      -- = not tested                                                          

The compounds of the present invention and their salts are useful as herbicides and can be applied in a variety of ways at various concentrations. In practice, the compounds or salts are formulated into herbicidal compositions, by admixture, in herbicidally effective amounts, with the adjuvants and carriers normally employed for facilitating the dispersion of active ingredients for agricultural applications, recognizing the fact that the formulation and mode of application of a toxicant may affect the activity of the materials in a given application. Thus, these active herbicidal compounds or salts can be formulated as granules of relatively large particle size, as wettable powders, as emulsifiable concentrates, as powdery dusts, as flowables, as solutions or as any of several other known types of formulations, depending upon the desired mode of application. These formulations may contain as little as about 0.5% to as much as about 95% or more by weight of active ingredient. A herbicidally effective amount depends upon the nature of the seeds or plants to be controlled and the rate of application varies from about 0.01 to approximately 10 pounds per acre, preferably from about 0.02 to about 4 pounds per acre.

Wettable powders are in the form of finely divided particles which disperse readily in water or other dispersants. The wettable powder is ultimately applied to the soil either as a dry dust or as a dispersion in water or other liquid. Typical carriers for wettable powders include fuller's earth, kaolin clays, silicas and other readily wet organic or inorganic diluents. Wettable powders normally are prepared to contain about 5% to about 95% of the active ingredient and usually also contain a small amount of wetting, dispersing, or emulsifying agent to facilitate wetting and dispersion.

Emulsifiable concentrates are homogeneous liquid compositions which are dispersible in water or other dispersant, and may consist entirely of the active compound or salt with a liquid or solid emulsifying agent, or may also contain a liquid carrier, such as xylene, heavy aromatic naphthal, isophorone and other non-volatile organic solvents. For herbicidal application, these concentrates are dispersed in water or other liquid carrier and normally applied as a spray to the area to be treated. The percentage by weight of the essential active ingredient may vary according to the manner in which the composition is to be applied, but in general comprises about 0.5% to 95% of active ingredient by weight of the herbicidal composition.

Granular formations wherein the toxicant is carried on relatively coarse particles, are usually applied without dilution to the area in which suppression of vegetation is desired. Typical carriers for granular formulations include sand, fuller's earth, attapulgite clay, bentonite clays, montmorillonite clay, vermiculite, perlite and other organic or inorganic materials which absorb or which may be coated with the toxicant. Granular formulations normally are prepared to contain from about to about 25% of active ingredients which may include surface-active agents such heavy aromatic naphthas, kerosene or other petroleum fractions, or vegetable oils; and/or stickers such as destrins, glue or synthetic resins.

Typical wetting, dispersing or emulsifying agents used in agricultural formulations include, for example, the alkyl and alkylaryl sulfonates and sulfates and their salts; polyhydric alcohols; polyethoxylated alcohols; esters and fatty amines; and other types of surface-active agents, many of which are available in commerce. The surface-active agent, when used, normally comprises from 0.1% to 15% by weight of the herbicidal composition.

Dusts, which are free-flowing admixtures of the active ingredient with finely divided solids such as talc, clays, flours and other organic and inorganic solids which act as dispersants and carriers for the toxicant, are useful formulations for soil-incorporating application.

Pastes, which are homogeneous suspensions of a finely divided solid toxicant in a liquid carrier such as water or oil, are employed for specific purposes. These formulations normally contain about 5% to about 95% of active ingredient by weight, and may also contain small amounts of a wetting, dispersing or emulsifying agent to facilitate dispersion. For application, the pastes are normally diluted and applied as a spray to the area to be affected.

Other useful formulations for herbicidal applications include simple solutions of the active ingredient in a dispersant in which it is completely soluble at the desired concentration, such as acetone, alkylated naphthalenes, xylene and other organic solvents. Pressurized sprays, typically aerosols, wherein the active ingredient is dispersed in finely-divided form as a result of vaporization of a low boiling dispersant solvent carrier, such as the Freons, may also be used.

The phytotoxic compositions of this invention can be applied to the plants in the conventional manner. Thus, the dust and liquid compositions can be applied to the plant by the use of power-dusters, boom and hand sprayers and spray dusters. The compositions can also be applied from airplanes as a dust or a spray or by rope wick applications because they are effective in very low dosages. In order to modify or control growth of germinating seeds or emerging seedlings, as a typical example, the dust and liquid compositions can be applied to the soil according to conventional methods and can be distributed in the soil to a depth of at least 1/2 inch below the soil surface. It is not necessary that the phytotoxic compositions be mechanically admixed with the soil particles since these compositions can also be applied merely by spraying or sprinkling the surface of the soil. The phytotoxic compositions of this invention can also be applied by addition to irrigation water supplied to the field to be treated. This method of application permits the penetration of the compositions into the soil as the water is absorbed therein. Dust compositions, granular compositons or liquid formations applied to the surface of the soil can be distributed below the surface of the soil by conventional means such as discing, dragging or mixing operations. In the following examples the herbicidal compound can be substituted with the herbicidal salt of the compound.

    __________________________________________________________________________     General Formula with Ranges                                                                         Specific Formula                                          __________________________________________________________________________     EMULSIFIABLE CONCENTRATE FORMULATIONS                                          Herbicidal compound                                                                           5-55  herbicidal coumpound                                                                        24                                           surfactant(s)  5-25  proprietary blend of oil-                                                                   10                                           solvent(s)     20-90 soluble sulfonates and                                                   100%  polyoxyethylene ethers                                                         polar solvent                                                                               27                                                                petroleum hydrocarbon                                                                       39                                                                             100%                                         WETTABLE POWDER FORMULATIONS                                                   herbicidal compound                                                                           3-90  herbicidal compound                                                                         80                                           wetting agent  0.5-2 sodium dialkyl naphthalene                                                                  0.5                                          dispersing agent                                                                              1-8   sulfonate                                                 diluent(s)     8.5-87                                                                               sodium lignosulfonate                                                                       7                                                           100%  attapulgite clay                                                                            12.5                                                                           100%                                         EXTRUDED GRANULAR FORMULATIONS                                                 herbicidal compound                                                                           1-20  herbicidal compound                                                                         10                                           binding agent  0-10  lignin sulfonate                                                                            5                                            diluent(s)     70-99 calcium carbonate                                                                           85                                                          100%               100%                                         FLOWABLE FORMULATIONS                                                          herbicidal compound                                                                           20-70 herbicidal compound                                                                         45                                           surfactant(s)  1-10  polyoxyethylene ether                                                                       5                                            suspending agent(s)                                                                           0.05-1                                                                               attagel      0.05                                         antifreeze agent                                                                              1-10  propylene glycol                                                                            10                                           antimicrobial agent                                                                           1-10  1,2-benzisothiazoline-3-one                                                                 0.03                                         antifoam agent 0.1-1 silicone defoamer                                                                           0.02                                         solvent        7.95-77.85                                                                           water        39.9                                                        100%               100%                                         __________________________________________________________________________

When salts are used as the active ingredient in the herbicidal compositions of this invention it is recommended to use salts that are agriculturally acceptable.

The phytotoxic compositions of this invention can also contain other additives, for example, fertilizers, other herbicides and other pesticides, used as adjuvant or in combination with any of the above-described adjuvants. Fertilizers useful in combination with the active ingredients include, for example, ammonium nitrate, urea and superphosphate.

The herbicidal compounds of this invention can be used in combination with other herbicidal compounds for broader spectrum control of undesirable vegetation. Examples of other herbicidal compounds are as follows:

1. ANILIDES

Alachlor--2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide

Metolachlor--2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide

Propanil--N-(3,4-dichlorophenyl)propionanilide

2. TRIAZINES

Atrazine--2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine

Cyanazine--2-chloro-4-(1-cyano-1-methylethylamino)-6-ethylamino-s-triazine

Metribuzin--4-amino-6-tert-butyl-3-(methylthio)-1,2,4-triazin-5(4H)-one

3. THIOCARBAMATES

Molinate--S-ethyl hexahydro-1H-azepine-1-carbothioate

Butylate--S-ethyl diisobutylthiocarbamate

4. UREAS

Monuron--3-(p-chlorophenyl)-1,1-dimethylurea

Linuron--3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea

5. TOLUIDINES

Trifluralin--α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine

Pendimethalin--N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine

6. HORMONES

2,4D--(2,4-dichlorophenoxy) acetic acid

MCPA--(2-methyl-4-chlorophenoxy) acetic acid

7. DIAZINES

Bentazon--3-isopropyl-1H-2,3,1-benzothiadiazin-4(3H)-one 2,2-dioxide

Oxadiazon--2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ² -1,3,4-oxadiazolin-5-one

8. DIPHENYL ETHERS

Acifluorfen--sodium 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate

Fluazifop-butyl--(±)-butyl 2-[4[(5-trifluoromethyl)-2-pyridinyl)oxy]phenoxy]propanoate

Chlomethoxynil--2,4-dichlorophenyl 3-methoxy-4-nitrophenyl ether

9. IMIDAZOLINONES

Imazaquin--2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-3-quinoline carboxylic acid

10. SULFONYL UREAS

Bensulfuron methyl--methyl 2-((((((4,6-dimethoxypyrimidin-2-yl)-amino)carbonyl)amino)sulfonyl-1)methyl)benzoate

Chlorimuron ethyl--ethyl 2-(((((4-chloro-6-methoxypyrimidin-2-yl)amino)carbonyl)amino)sulfonyl)benzoate

11. MISCELLANEOUS COMPOUNDS

Dimethazone--2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone

Norflurazon--4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3-(2H)-pyridazinone

Dalapon--2,2-dichloropropionic acid

Glyphosate--isopropyl amine salt of N-(phosphonomethyl)glycine

Fenoxaprop-ethyl--(+)-ethyl-2,4-((6-chloro-2-benzoxazolyloxy)phenoxy)propanoate 

What is claimed is:
 1. A compound of the formula ##STR13## wherein R is halogen; C₁ -C₂ alkyl; C₁ -C₂ alkoxy; trifluoromethoxy; difluoromethoxy; nitro; cyano; C₁ -C₂ haloalkyl; R^(a) SO_(n) -- wherein n is 0 or 2 and R^(a) is C₁ -C₂ alkyl, trifluoromethyl or difluoromethyl;R¹ is hydrogen or C₁ -C₄ alkyl; R² is hydrogen or C₁ -C₄ alkyl; R³ is hydrogen or C₁ -C₄ alkyl; R⁴ is hydrogen or C₁ -C₄ alkyl; and R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; and (13) --N(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined; and their salts.
 2. A compound of claim 1 wherein R is chlorine, bromine, methyl, methoxy, nitro, trifluoromethyl or methylsulfonyl; R¹, R², R³ and R⁴ are hydrogen or methyl; R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; or (13) --N--(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined.
 3. A compound of claim 2 wherein R⁵ and R⁶ are independently are hydrogen; chlorine; fluorine; bromine; methyl; C₁ -C₄ alkoxy; trifluoromethoxy; cyano; nitro; trifluoromethyl; R^(b) SO_(n) -- wherein n is the integer 0 or 2 and R^(b) is methyl, chloromethyl, trifluoromethyl; ethyl or n-propyl, R^(e) C(O)-- where R^(e) is C₁ -C₄ alkyl; or SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined, and R⁵ is in the 3-position and R⁶ is in the 4-position.
 4. A compound of claim 2 wherein R⁵ is hydrogen and R⁶ is hydrogen, chlorine, bromine, fluorine, cyano, trifluoromethyl or R^(b) SO₂ wherein R^(b) is C₁ -C₄ alkyl or C₁ -C₄ haloalkyl.
 5. The compounds of claim 2 wherein R is nitro; R¹ is hydrogen or methyl; R² is hydrogen or methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is hydrogen.
 6. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is hydrogen; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is 4-trifluoromethyl.
 7. The compound of claim 2 wherein R is nitro; R¹ is hydrogen; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is 4-trifluoromethyl.
 8. The compound of claim 2 wherein R is chlorine; R¹ is hydrogen; R² is hydrogen; R³ is hydrogen; R⁴ is hydrogen; R⁵ is hydrogen; and R⁶ is hydrogen.
 9. The compound of claim 2 wherein R is chlorine; R¹ is hydrogen; R² is hydrogen; R³ is hydrogen; R⁴ is hydrogen; R⁵ is hydrogen; and R⁶ is 4-chlorine.
 10. The method of controlling undesirable vegetation comprising applying to the area where control is desired, an herbicidally effective amount of a compound having the formula ##STR14## wherein R is halogen; C₁ -C₂ alkyl; C₁ -C₂ alkyl; C₁ -C₂ alkoxy; trifluoromethoxy; difluoromethoxy; nitro; cyano; C₁ -C₂ haloalkyl; R^(a) SO_(n) -- wherein n is 0 or 2 and R^(a) is C₁ -C₂ alkyl; trifluoromethyl or difluoromethyl;R¹ is hydrogen or C₁ -C₄ alkyl; R² is hydrogen or C₁ -C₄ alkyl; R³ is hydrogen or C₁ -C₄ alkyl; R⁴ is hydrogen or C₁ -C₄ alkyl; and R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; and (13) --N(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined; and their salts.
 11. The method of claim 10 wherein R is chlorine, bromine, methyl, methoxy, nitro, trifluoromethyl, or methylsulfonyl; R¹, R², R³ and R⁴ are hydrogen or methyl; R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; or (13) --N--(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined.
 12. The method of claim 11 wherein R⁵ and R⁶ are independently are hydrogen; chlorine; fluorine; bromine; methyl; C₁ -C₄ alkoxy; trifluoromethoxy; cyano; nitro; trifluoromethyl; R^(b) SO_(n) -- wherein n is the integer 0 or 2 and R^(b) is methyl, chloromethyl, trifluoromethyl, ethyl, or n-propyl; R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl; or SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined and R⁵ is in the 3-position and R⁶ is in the 4-position.
 13. The method of claim 11 wherein R⁵ is hydrogen and R⁶ is hydrogen, chlorine, bromine, fluorine, cyano, trifluoromethyl, or R^(b) SO₂ wherein R^(b) is C₁ -C₄ alkyl or C₁ -C₄ haloalkyl.
 14. The method of claim 10 wherein R is nitro; R¹ is hydrogen or methyl; R² is hydrogen or methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is hydrogen.
 15. The method of claim 10 wherein R is nitro; R¹ is methyl; R² is hydrogen; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-trifluoromethyl.
 16. The method of claim 10 wherein R is nitro; R¹ is methyl; R² is hydrogen; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is 4-trifluoromethyl.
 17. The method of claim 10 wherein R is chlorine; R¹ is hydrogen; R² is hydrogen; R³ is hydrogen; R⁴ is hydrogen; R⁵ is hydrogen; and R⁶ is hydrogen.
 18. The method of claim 10 wherein R is chlorine; R¹ is hydrogen; R² is hydrogen; R³ is hydrogen; R⁴ is hydrogen; R⁵ is hydrogen; and R⁶ is 4-chlorine.
 19. An herbicidal composition comprising an herbicidally active 3-(substituted benzoyl)-3:2:1-bicyclooctan-2,4-dione or a salt thereof and an inert carrier therefor.
 20. The herbicidal composition of claim 19 wherein the 3-(substituted benzoyl)-3:2:1-bicyclooctan-2,4-dione is a compound of the formula ##STR15## wherein R is halogen; C₁ -C₂ alkyl; C₁ -C₂ alkoxy; trifluoromethoxy; difluoromethoxy; nitro; cyano; C₁ -C₂ haloalkyl; R^(a) SO_(n) -- wherein n is 0 or 2 and R^(a) is C₁ -C₂ alkyl, trifluoromethyl or difluoromethyl;R¹ is hydrogen or C₁ -C₄ alkyl; R² is hydrogen or C₁ -C₄ alkyl; R³ is hydrogen or C₁ -C₄ alkyl; R⁴ is hydrogen or C₁ -C₄ alkyl; and R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy); (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; and (13) --N(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined; and their salts.
 21. The composition of claim 20 wherein R is chlorine, bromine, methyl, methoxy, nitro, trifluoromethyl or methylsulfonyl; R¹, R², R³ and R⁴ are hydrogen or methyl; R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; or (13) --N--(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined.
 22. The composition of claim 21 wherein R⁵ and R⁶ are independently are hydrogen; chlorine; fluorine; bromine; methyl; C₁ -C₄ alkoxy; trifluoromethoxy; cyano; nitro; trifluoromethyl; R^(b) SO_(n) -- wherein n is the integer 0 or 2 and R^(b) is methyl, chloromethyl, trifluorometyl, ethyl, or n-propyl; R^(e) C(O)-- where R^(e) is C₁ -C₄ alkyl; or SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined and R⁵ is in the 3-position and R⁶ is in the 4-position.
 23. The composition of claim 21 wherein R⁵ is hydrogen and R⁶ is hydrogen, chlorine, bromine, fluorine, cyano, trifluoromethyl or R^(b) SO₂ wherein R^(b) is C₁ -C₄ alkyl or C₁ -C₄ haloalkyl.
 24. The composition of claim 21 wherein R is nitro; R¹ is hydrogen or methyl; R² is hydrogen or methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is hydrogen.
 25. The composition of claim 21 wherein R is nitro; R¹ is methyl; R² is hydrogen; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is 4-trifluoromethyl.
 26. The composition of claim 21 wherein R is nitro; R¹ is hydrogen; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; and R⁶ is 4-trifluoromethyl.
 27. The composition of claim 21 wherein R is chlorine; R¹ is hydrogen; R² is hydrogen; R³ is hydrogen; R⁴ is hydrogen; R⁵ is hydrogen; and R⁶ is hydrogen.
 28. The composition of claim 21 wherein R is chlorine; R¹ is hydrogen; R² is hydrogen; R³ is hydrogen; R⁴ is hydrogen; R⁵ is hydrogen; and R⁶ is 4-chlorine.
 29. The method of controlling undesirable vegetation comprising applying to the area where control is desired, an herbicidal composition comprising an herbicidally active 3-(substituted benzoyl)-3:2:1-bicyclooctan-2,4-dione or its salt and an inert carrier therefor.
 30. Intermediate compounds of the structural formula ##STR16## wherein R is halogen; C₁ -C₂ alkyl; C₁ -C₂ alkoxy; trifluoromethoxy; difluoromethoxy; nitro; cyano; C₁ -C₂ haloalkyl; R^(a) SO_(n) -- wherein n is 0 or 2 and R^(a) is C₁ -C₂ alkyl; trifluoromethyl or difluoromethyl;R¹ is hydrogen or C₁ -C₄ alkyl; R² is hydrogen or C₁ -C₄ alkyl; R³ is hydrogen or C₁ -C₄ alkyl; R⁴ is hydrogen or C₁ -C₄ alkyl; and R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; and (13) --N(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined. 